Disposable diaper having adhesive tabs and release strips therefor permanently attached at marginal edges of diaper

ABSTRACT

A disposable diaper adhesive closure means is provided having an adhesive tab protected by a releasable cover strip permanently attached to the diaper, thus eliminating the need for disposal of the cover strip by the consumer when the diaper is applied.

United States Patent 7 U9] Tritsch Dec. 16, 1975 DISPOSABLE DIAPERHAVING ADHESIVE TABS AND RELEASE STRIPS THEREFOR PERMANENTLY ATTACHED ATMARGINAL EDGES OF DIAPER [75] Inventor: Ludwig Tritsch, Wilmette, 111.

[73] Assignee: Johnson & Johnson, New

Brunswick, NJ.

221 Filed: Nov. 20, 1974 21 Appl. No.: 525,607

[52] US. Cl 128/287; 128/284 [51] Int. Cl. A61F 13/16 [58] Field ofSearch 128/284, 287, 290 R [56] References Cited UNITED STATES PATENTS3,196,874 7/1965 Hrubecky 128/287 3,776,234 12/1973 l-loey 128/2873,840,013 10/1974 Mesek 128/287 Primary E.raminerAldrich F. Medberry 4Claims, 4 Drawing Figures Us. Patent 1560. 16, 1975 3,926,191

DISPOSABLE DIAPER HAVING ADHESIVE TABS AND RELEASE STRIPS THEREFORPERMANENTLY ATTACHED AT MARGINAL EDGES OF DIAPER BACKGROUND OF THEINVENTION This invention relates to disposable diapers. Moreparticularly, this invention relates to disposable diapers adapted to besecured in place by adhesive tabs.

Disposable diapers provide substantial advantages in convenience overdiapers intended to be laundered and reused, particularly when they areused away from home. In recent years, many different disposable diapershave been proposed and some have been successful in the marketplace.Typical disposable diaper structures comprise a moisture-retaining layerof high liq uid-holding capacity and a moisture-impervious backingsheet, generally made of a plastic film such as polyethylene film or thelike. Typical disposable diaper structures are shown in US. Pat. No.3,612,055 to Mesek et al. and in US. Pat. No. Re. 26,151 to Duncan etal.

As may be seen from the above-cited patents, it is desirable to obviatethe problems that are inherent in closure systems which utilizeextraneous fasteners such as safety pins, snaps and Zippers. To this endadhesive closure systems have presented acceptable solutions.

One of the most convenient adhesive systems that has been developed todate is the system, shown in the above-cited patents, in which adhesivetabs are ad hered to the backing sheet extending outwardly from oppositesides of the diaper at one end thereof, and in which the exposed areasof the adhesive strips are pro- -vided with readily separable coverstrips which protect the exposed areas until ready for use. However,disposable diapers using an adhesive closure system of this general typehave the disadvantage that the consumer has to dispose of the coverstrips when they are separated from the adhesive tabs. This is aninconvenience to the consumer who is placing the diaper on a baby atabout the same time.

An illustrative prior an adhesive system having cover strips permanentlyattached to the diaper is disclosed in US. Pat. No. 3,646,937 toGellert. The Gellert arrangement has the disadvantage of having arelease film permanently anchored to the inside surface of the diaper,where it can possibly come into contact with a babys tender skin.Additional disadvantages are the complexities and expense which areadded to the manufacturing process by requiring each adhesive closure tobe manipulated on the front side, around the edge, and on to the backside of the diaper, instead of handling the adhesive closure on one sideonly.

SUMMARY OF THE INVENTION In this invention, the adhesive tab which isused to secure the diaper on a baby is attached at one end thereof to abacking sheet of the diaper while the other end of the tab, the freeworking end, presents a tacky surface facing in the same direction asthe diaper inside surface and which is releasably covered by arelease-coated surface of a cover strip which, in turn, is permanentlyattached to the diaper. One end of the cover strip is at tached to thebacking sheet of the diaper and the other end is provided with agrippable end tab to facilitate the subsequent separation of the coverstrip from the adhesive tab.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view, partlybroken away to show interior detail, of an open unfolded diaper inaccordance with one embodiment of the invention;

FIG. 2 is a fragmentary cross-sectional view of the diaper of FIG. 1taken along plane 2-2 and shown on an enlarged scale;

FIG. 3 is a fragmentary cross-sectional view similar to FIG. 2,illustrating an alternate embodiment of the invention; and

FIG. 4 is a perspective view of the diaper of FIG. I in a configurationassumed by the diaper when placed about an infant.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Disposable diaper 10,illustrated in FIGS. 1 and 4, is of substantially quadrilateralconfiguration and presents inside surface 11 for direction toward aninfant and outside surface 12 for direction away from the infant.Adhesive tabs 13 and 14 are attached to diaper 10 for securing diaper 10about an infant. The tacky adhesive surfaces of tabs 13 and 14 arecovered by protective cover strips 15 and 16, respectively, which arepermanently attached to respective opposed marginal edges of diaper 10.In FIG. 1, adhesive tab 13 is shown with cover strip 15 partially liftedtherefrom, andadhesive tab 14 is shown with cover strip 16 in place andcovering the entire adhesive surface of tab 14. The cover strips such asstrips 15 and 16 can be made of paper coated on one side with a suitablerelease coating such as a silicone composition, or they can be made of asmooth polyolefin film provided with a non-tacky surface, or the like.

Diaper 10 comprises a moisture-retaining layer made up ofmoisture-pervious facing sheet 17, overlying absorbent pad 18, andbacking sheet 19 made of a moisture-impervious material. Absorbent pad18 is somewhat smaller than backing sheet 19 and is centrally disposedthereon; however, pad 18 can be made coextensive with backing sheet 19if desired. Facing sheet 17 is substantially coextensive with backingsheet 19. Both facing sheet 17 and pad 18 can be anchored to backingsheet 19 by means of adhesive beads 20, or in any other convenientmanner. For example, if backing sheet 19 is made of a thermoplasticmaterial, facing sheet 17 and pad 18 can be attached thereto by heatbonding.

Referring to FIG. 2, adhesive tab 14, having fixed end 21 and anoutwardly extending free working end 22, is attached to backing sheet 19on the diaper outside surface by securing fixed end 21 thereto withpressuresensitive adhesive layer 23 which also covers free working end22. If backing sheet 19 is a thermoplastic web, fixed end 21 can also beattached to backing sheet 19 by heat bonding in which case adhesivelayer 23 is coextensive only with free working end 22.

Cover strip 16 extends over that portion of adhesive layer 23 whichcovers free working end 22 and is releasably held thereon. One end ofcover strip 16 is affixed to backing sheet 19 by adhesive bead 24 alongthe longitudinal margin of diaper I0, and the distal end of cover strip16 extends longitudinally beyond the tacky surface on free working end22 and provides flat grippable end tab 25 which facilitates theuncovering of adhesive layer 23 on free working end 22, which faces inthe same direction as inside surface 11, when the diaper is prepared foruse. When the diaper is applied about the infant, cover strip 16 can befolded out of the way in any convenient manner.

Another embodiment of the present invention is shown in FIG. 3 whereadhesive tab 26 comprises fixed end 29 and free working end 33 which isreleasably covered by curlable cover sheet 31 having coiled grippableend tab 32. Fixed end 29 is secured to backing sheet 27 by means ofpressure-sensitive adhesive layer 30 which also covers free working end33 and which provides an exposed tacky surface when cover sheet 31 islifted therefrom. Adhesive bead 34 permanently affixes cover sheet 31 tobacking sheet 27 in a manner hereinaboveset forth. Coil 31, shown inphantom and abutting facing sheet 28, illustrates the configurationassumed by cover sheet 31 when that portion of adhe sive layer 30 whichcovers free working end 33 is exposed. Curlable cover sheet 31 can bemade of any suitable material having a memory and to which releaseproperties can be imparted. Illustrative of such materials areprestressed polyethylene terephthalate webs having a non-tacky releasesurface, release sheets having embedded therein longitudinally-extendingstrands of coiling material, coiled webs produced by skiving anultra-high molecular weight polyethylene rod, and the like. In a stillfurther embodiment of this invention only the grippable end tab of thecover sheet can be provided with coiling properties.

Adhesive tabs suitable for the purposes of the present invention can bemade from a wide variety of materials, provided that such materials aresufficiently flexible. Particularly preferred materials for this purposeare polyalkylene webs such as polyethylene sheet, polypropylene sheet,and the like.

The pressure-sensitive adhesive layers such as layer 23 and layer 30 areformed by applying a coating of a pressure-sensitive adhesivecomposition known in the art to the appropriate surfaces of tabs 14 and26. The applied adhesive shall have good tack, good cohesive strength,good resistance to moisture and good resistance to aging. Illustrativeof such adhesive compositions are mixtures of natural or syntheticrubber, zinc oxide, and various resins, also latices of natural orsynthetic rubber, or water dispersions of acrylic tacky polymers orcopolymers.

Several different types of facing materials may be used for diaperfacing sheets 19 and 27. For example, facing sheets 19 and 27 may bemade up of a mixture of fibers consisting predominantly of inexpensiveshort cellulosic fibers such as wood pulp fibers or cotton linters, inamounts of about 75 percent to about 98 percent, the balance beingtextile length fibers such as rayon as described in U.S. Pat. No.3,663,348 to Liloia et a1.

Facing sheet materials suitable for use in this invention can havefabric weights in the range of about 1 to oz/yd and densities of lessthan 0.15 g/cc, generally in the range between 0.05 and 0.1 g/cc. Thedry strength of the facing sheet for fabric having a weight of about 1.5oz/yd is at least 0.15 lbs/in of width in the machine direction and atleast 0.1 lbs/in of width in the cross direction. Such fabrics haveunusually good elongation, loft, softness, and drape characteristics incomparison to prior products incorporating any substantial amount ofshort fibers.

Facing sheets 19 and 27 may also be made of an apertured, nonwovenfabric which is formed, for example,

4 in accordance with the teachings of commonly assigned U.S. Pat. Nos.2,862,251; 3,081,514; and 3,081,515. Briefly, such fabrics areforaminous structures wherein groups or groupings of fibers have beenrearranged from a fibrous nonwoven starting web into positionssurrounding less dense fabric portions by passage of a fluid through thestarting material. The fibers within the groupings are mechanicallyinterlocked, and may be arranged into various patterns, as is well knownby those skilled in the art. A suitable binder may be utilized to helpretain the fibers in their rearranged locations, as is also well knownby those skilled in the art. The fabric can be made of naturallyoccurring fibers, synthetic fibers, or blends thereof. Typical facingsheets made of a polyester type material can have a weight of about 0.75oz/yd In addition, facing sheets 17 and 28 can be formed of anonaperatured material, such as a nonwoven isotropic web, or the like.In all of the aforementioned facing materials, the material should berelatively hydrophobic so as to retard wicking within the facing layer.

Highly moisture-absorbent fibrous pad or batt 18, which usually issubstantially rectangular in shape but smaller than the facing sheet andthe backing sheet, can be formed in accordance with the teachings ofU.S. Pat. No. 3,612,055 to Mesek et a1. If desired, a highlymoisture-absorbent layer can be provided substantially coextensive withthe backing sheet and the facing sheet.

A suitable backing sheet material for the diapers embodying the presentinvention can be an opaque polyethylene web about 0.001 inch thick.Another suitable material for this purpose is a polyethyleneterephthalate web having a thickness of about 0.0005 inch. Typicaldisposable diapers which can be fitted with tab-type adhesive fastenersdescribed hereinabove are shown in U.S. Pat. No. 3,612,055 to Mesek etal. and in U.S. Pat. No. 3,683 ,916 to Mesek et al. Other suitabledisposable diaper structures which can be improved by the presenttab-type fasteners are shown in U.S. Pat. No. Re. 26,151 to Duncan etal.

In use, a diaper equipped with the adhesive fasteners of the presentinvention is applied to the infant by laying out the diaper on asuitable flat surface and placing the infant thereon so that thewaist-underlying end of the diaper is that having the fastener means.The other end of the diaper then extends downwardly between the infantslegs. Next, the downwardly-extending end of the diaper is brought upbetween the infants legs to a position contiguous with the front of theinfants waist. The diaper is thereafter secured to the infant by placingthe corners of the waist portion of the abdomen-covering end as fararound the infants waist as they will go and by bringing the corners ofthe underlying end of the diaper into an overlapping relationship withthe aforementioned corners so that the diaper snugly encircles theinfants waist and provides a custom fit. The adhesive fasteners are thenprepared for use by grasping cover strip terminal portions such as flatportion 25 or coiled portion 32 and pulling the cover strip away fromthe adhesive surface on the free end of the adhesive tab. The tabs arethen used to secure the diaper in the desired position by simply urgingthe pressure-sensitive adhesive surfaces in contact with the adjacentouter surface of the diaper.

The foregoing description and the drawing are illustrative but are notto be taken as limiting. Still other variations and modifications arepossible without departing from the spirit and scope of the presentinvention.

I claim:

1. In combination with a disposable diaper having an inside surface fordirection toward an infant when the 6 1 said cover strip extendinglongitudinally beyond said tacky surface and being permanently attachedto said backing sheet at a marginal location thereof. 2. The combinationin accordance with claim 1 diaper is worn by that infant and an outsidesurface for 5 wherein that portion of the cover strip which extendsdirection away from said infant and provided with a moisture-retaininglayer and a moisture-impervious backing sheet, an improved adhesive tabhaving a fixed end secured to said backing sheet on the outside surfaceof the diaper and at a marginal location thereof, and an outwardlyextending free end provided with a tacky surface facing in the samedirection as said inside surface; and a cover strip provided with arelease coating on one surface thereof, releasably attached to, andcovering said tacky surface;

longitudinally beyond said tacky surface is flat and provides agrippable end tab.

3. The combination in accordance with claim 1 wherein that portion ofthe cover strip which extends longitudinally beyond said tacky surfaceis coiled and provides a grippable end tab.

4. The combination in accordance with claim 1 wherein said cover stripis curlable and forms a coil upon lifting from said tacky surface.

1. In combination with a disposable diaper having an inside surface fordirection toward an infant when the diaper is worn by that infant and anoutside surface for direction away from said infant and provided with amoisture-retaining layer and a moisture-impervious backing sheet, animproved adhesive tab having a fixed end secured to said backing sheeton the outside surface of the diaper and at a marginal location thereof,and an outwardly extending free end provided with a tacky surface facingin the same direction as said inside surface; and a cover strip providedwith a release coating on one surface thereof, releasably attached to,and covering said tacky surface; said cover strip extendinglongitudinally beyond said tacky surface and being permanently attachedto said backing sheet at a marginal location thereof.
 2. The combinationin accordance with claim 1 wherein that portion of the cover strip whichextends longitudinally beyond said tacky surface is flat and provides agrippable end tab.
 3. The combination in accordance with claim 1 whereinthat portion of the cover strip which extends longitudinally beyond saidtacky surface is coiled and provides a grippable end tab.
 4. Thecombination in accordance with claim 1 wherein said cover strip iscurlable and forms a coil upon lifting from said tacky surface.